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I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.

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A couple of things have happened recently that lead me to post about projecting the amount of CPU that's zIIP eligible.
(Everything in this post applies equally to zAAPs, of course.) When we first introduced z/OS specialty engines we introduced the "Project CPU" mechanism, reporting most notably via RMF.
(I emphasise "z/OS" because ICF and IFL engines, which don't run z/OS, don't have such a... [More]

Prompted by Troy Coleman's article zEC12 and zIIP Processors I thought I'd write about how I see the future for zAAPs. First, his article does a good job of covering the area. So I recommend you read it. Troy mentions the "zAAP on zIIP" function - which allows zAAP-eligible work to run on a zIIP. It's not news and it's a good piece of function: It means you can fill zIIPs more readily, making them... [More]

I'm not a capacity planner but I play one on TV 1 sometimes. A customer asked me about the subject of zAAP Capacity Planning so I thought I'd post a few thoughts here. (Almost everything I say here is equally true of a zIIP.) The main point is I don't think it terribly different from regular CPU Capacity Planning. But there are some quirks: While we do have queuing we also have Crossover. But at... [More]

The very first computer game I ever played was called Rhino and it ran on a Commodore PET. The school had been lent one for a fortnight. (I don't know why as we didn't go on to buy any, instead getting a single RML 380Z.) Imagine a character-grid screen where the rhino's are represented by pi symbols that chase you as you try to move from A to B. It was written in BASIC and allowed from 1 to 10... [More]

I was going to start this post with an apology. But, as any sensible blogger would, I left it a few days to write this. Now I realise that there's a wider point than the "I was wrong" one. (But I was wrong - in a way that I think many other people might've been wrong too.) So let me talk about two things in this post: zAAP and zIIP Delay. How I came to be wrong and what we can all... [More]

It's been an awfully long time since I wrote When Good Work Doesn't Go To zIIP / zAAP Heaven . And too long since I posted anything at all. In fact I had a bunch of posts in my brain until this morning when a customer asked me a question which turned into this blog post. (Those posts are still in my brain and will probably see the light of day eventually, including one based on a customer... [More]

A need has arisen for pretty printing XML. This post includes some Python code to do it.
I've been working with the OpenOffice.org ODP presentation file format recently: I want to generate presentations from application code.
An ODP file is a structured zip file. Among other items it contains an XML file - content.xml - which describes the pages in the presentation. content.xml... [More]

In the distant past I've written about using DFSORT to parse XML. This post (and two follow-on posts) will describe
an experiment to make such processing much more robust. In this post I'll talk about what the problem I'm trying to solve is. And why. And a brief outline of my solution. About XML This isn't meant to be the most detailed description of XML, nor a complete list of where it's used. I... [More]

I'm towards the end of revamping our analysis code to support (z9) and z/OS R.8. What took us so long? :-) I'm telling you this for two reasons: So you know what there is that might slow you down. So you have some view as to whether we can competently process your data. :-) System z9 About the only change in instrumentation between z990 and z9 is the separation of specialty engines into pools. But... [More]

Last week I was at the System z Tech Conference (again getting my zeds mixed up with my zees). :-) I presented 4 times, one of which was a repeat. What's especially nice is that I got 87 attendees for the "Memory Matters in 2008" presentation - spread across 2 sessions. This was despite the second time being the very last session of the conference... and 22 people still showed up to that! So... [More]

Hmmm: IBM press release on the gameframe . I'd like to see a lot more detail on this before I go "whoopie!" but it does sound like an intriguing idea. It would be the first "specialty" engine to actually feature different hardware. Reminds of me of the 3090 Vector Facility but it's really nothing like it. And at this stage there's nothing about what will actually be shipped. Still, I'm happy to... [More]